This proposal presents theoretical approaches to some problems in neurophysiology. Electrostatic model and molecular dynamics calculations descriptive of the process of ion permeation through membrane channels are proposed. The electrostatic model is used to calculate the effect that pore structure, charge distributions at either the watermembrane interface or within the pore former, and electrolyte composition have on the electrostatic energy profile and on the electric field generated by a transmembrane potential. The molecular dynamics calculations focus on local structural features that might effect channel selectivity. The results of these calculations will be used to refine and to test the models used to portray biological channels.